Foam Fire Extinguisher Uses

Foam fire extinguishers are one of five primary types of fire extinguisher commonly available in the U.S. today. Foam fire extinguishers have the advantage of being able to extinguish fires progressively by smothering the fire and depriving it of oxygen without fear of flashback, as can be the case with other power fire extinguishers. There are several variations in the chemical composition of foam fire extinguishers, making some better at fighting certain types of fire than others. However, as a general rule foam fire extinguishers are used for Class A and B fires, although occasionally they also are used for Class D fires.

Class A Fires

• Cloth, wood, rubber, paper and many types of plastics are grouped together as 'ordinary combustibles,'' which cause Class A fires. If any of these materials should catch fire, a foam fire extinguisher will easily extinguish it. Foam fire extinguishers are not used regularly to fight Class A fires, however, as water extinguishers work equally well and are cheaper to produce.

Class B Fires

• Foam fire extinguishers are primarily used to putout Class B fires, which include fires started by grease, gasoline, oil or oil-based paints. This type of fire has a tendency to spread very quickly so it is important that you react immediately to an outbreak. Foam fire extinguishers work by smothering the flammable liquid, depriving it of the oxygen it needs to burn.

Class D Fires

• It is not advisable to use foam fire extinguishers on a Class D fire unless you are certain of what you are doing. Class D fires are metal fires and usually occur only in factories or industrial workplaces. Certain types of foam fire extinguisher, such as Arctic Fire, are used in the steel industry to put out metal fires. Other types of foam fire extinguisher contain small amounts of water that will exacerbate a metal fire if used on it.

Types of Foam Fire Extinguisher

• Most foam fire extinguishers are used for the same or similar purposes, that is extinguishing Class A and B fires, so it is not necessary to know the different types. There are subtle differences in chemical composition between foam fire extinguishers, however, and these are denoted by a code on the side of the canister. Aqueous film forming foam (AFFF) is the most commonly used type of foam fire extinguisher. Alcohol-resistant aqueous film forming foams (AR-AFFF) are specially designed for fires started by alcohol. Film forming fluoroprotein (FFF) contains naturally occurring animal proteins in the foam and can cope with higher temperatures. The compressed air foam system (CAFS) is used to fight forest fires, and Arctic Fire, as mentioned, is designed to fight industrial Class D fires.